I start with a clock signal. That clock signal goes into a random shift register which spits out a different new voltage every time the clock ticks. The voltage goes into a voltage-controlled filter with its resonance control set high so it’ll ring if it stays on one voltage for more than a fraction of a second.

The bandpass output of that filter goes into the aux path of a (crunchy) digital delay – this means there’s feedback path between the delay and the filter which “remembers” what noise the filter was just making and feeds it back to the filter as an input. This creates a subtle fade effect from one “drip” to the next.